For about a year and a half I've been running my i5-4690K at 4.5GHz, and the base clock speed stayed at 99.76MHz exactly. No fluctuations at all. In the past 1-2 months, it's been running at around 99.87MHz, with occasional fluctuations down to 99.76MHz or up to 99.91MHz. Very recently, it began to drop occasionally to less than 80MHz. Should I be worried about these BCLK fluctuations? I'm not sure if this is a problem with my CPU or crappy motherboard (ASRock Z97 Pro3).